I can vouch for the same machine. I have a couple of tops that I started on one machine and continued on another. One of those tops is a UFO that I recently dug out and ended up having to scale down from a queen to a twin because my blocks were WAYYYYY off. Another quilt I plowed through basically fitting two different size blocks together into one quilt. Made it work...but it was work. I have since sworn that I will start and complete a project on ONE machine. I have no idea about the bobbin thread. I use the same thread top and bottom.